Aspiration properties of flexible and navigable suction ureteral access sheath (FANS) and flexible ureteroscope with direct-in-scope suction (DISS): an in-vitro experimental study by EAU young academic urologists (YAU) urolithiasis and endourology working group.

PURPOSE: To illustratively evaluate and compare the effectiveness of aspiration of 7.5Fr and 9.2Fr single-use flexible ureteroscopes with direct in-scope-suction (DISS) with a 12/14Fr flexible and navigable suction ureteral access sheath (FANS) in an in-vitro setting.

METHODS

Our experimental setup included a 6.5-size sterile glove, 2 mm and 4 mm stone fragments, and a porcine ureter. Three experimental scenarios were evaluated in the upper, middle and lower calyx: 1. Suction via 12/14Fr FANS, 2. Suction via 7.5Fr DISS, 3. Suction via 9.2Fr DISS.

RESULTS

Evacuation of the 2 mm stone was reported in all trials regardless of the used instrument. Aspiration and repositioning of the 4 mm fragment was observed from the upper calyx with all instruments. In the middle calyx, stone evacuation was successful in 5 out of 5 trials with 7.5Fr DISS, and 3 out of 5 with 12/14Fr FANS or 9.2Fr DISS. Stone relocation using suction with subsequent evacuation of the 4 mm fragment from the lower calyx was achieved in none of the trials with 12/14Fr FANS and only in 1 trial with 9.2Fr DISS scope whereas it was successful in 4 trials when 7.5Fr DISS was used. Collapse of the pelvicalyceal system (PCS) was more pronounced with the 12/14Fr FANS and 9.2Fr DISS scope (3-4 s) compared to 7.5Fr DISS scope (6-7 s).

CONCLUSION

In this study, the 7.5Fr single-use flexible ureteroscope was found to be superior in terms of stone extraction and relocation, while it seemed to have less impact on the collapse of the PCS compared to 9.2Fr DISS and 12/14Fr FANS.